In recent years, radio communication systems (wireless LAN) have been widely used and “HotSpots” have been increased at which mobile devices supporting this wireless LAN, for example, notebook personal computers can be connected to the Internet or other services in the public areas. As a plate-like antenna mountable in the notebook personal computer capable of using the wireless LAN at the HotSpot, a flat-plane antenna formed of a plate-like metal element has been known (for example, see Non-patent Document 1).
The metal element of the antenna is formed by a rectangular plate-like ground conductor and an “L” shaped radiation conductor extending in a long narrow form from the end portion of the ground conductor. The frequency used by the antenna is about 2.4 GHz and the radiation conductor extends by a length corresponding to about ¼ of a wavelength λ of the used frequency.
An inner conductor (center conductor) of a coaxial cable is electrically connected to the radiation conductor, and an outer conductor of the coaxial cable is electrically connected to the ground conductor.
Then, the antenna is designed to be supplied with power by using the coaxial cable.    [Non-patent Document 1] “Built-in Film Antenna for Mobile Devices using 2.4. GHz Band,” Technical Journal of Hitachi Cable, Ltd., No. 21 issued in January, 2002). Meanwhile, an antenna is known which is configured to be entirely flexible by forming a conductor thinly on a surface of a film-like base (for example, see Patent Document 1).    [Patent Document 1] Japanese Patent Application Publication No. 2005-277897).